Diffraction software

The X-ray powder diffraction (XRPD) pattern of a sample of atorvastatin calcium, Form-I, was recorded at room temperature on Bruker D8 Advance diffractometer (Karlsruhe, Germany), using nickel-filtered Cu Ka radiation. The sample was mounted in a polymethylmethacrylate sample holder, and analyzed in a continuous mode with a step size of 0.01° and a step time of 1 s over an angular range of 3-40° 26. The XRPD results are found in Fig. 1.18 and in Table 1.3, being evaluated with the DIFFRACplus EVA (version 9.0) diffraction software. 

New powder diffraction software tends to be announced in one or all of a small group of publications and forums. The main forums are the lUCr Journal of... 

Compared to powder diffraction software, single crystal refinement programs are currently more advanced for routine structure refinement (Table 17.25). Compared to existing Rietveld software, it can be less time consuming to use a... 

A first port of call for checking out available crystallographic software. Links to and mirrors of single crystal and powder crystallographic software. Includes tutorials for some of the software and lists of available software Free CD ROM containing various Internet available single crystal and powder diffraction software and resources. Mainly intended for academics and students in the developing world... 

Kcristal Linux versions and ports of powder diffraction software on free downloadable CD... 

X-ray diffraction software Crystallographic software interfacing and development for structural genomics University ofYork ... 

X-ray diffraction (XRD) measurements were taken on a Philips PW-1830 diffractometer, Cu Ka radiation (1 = 0.154 mn) being used at 40 kV and 25 mA between 20= 1-15°. The basal distances, di, were calculated from the first (001) Bragg reflections through the PW 1877 automated powder diffraction software. 

CCP13 2004 Fiber and Polymer Diffraction Software (Daresbury Lab, UK], 2004. http //www.ccpl3.ac.uk/software/software.htm. 

Powder diffraction studies with neutrons are perfonned both at nuclear reactors and at spallation sources. In both cases a cylindrical sample is observed by multiple detectors or, in some cases, by a curved, position-sensitive detector. In a powder diffractometer at a reactor, collimators and detectors at many different 20 angles are scaimed over small angular ranges to fill in the pattern. At a spallation source, pulses of neutrons of different wavelengdis strike the sample at different times and detectors at different angles see the entire powder pattern, also at different times. These slightly displaced patterns are then time focused , either by electronic hardware or by software in the subsequent data analysis. 

Five articles on polysaccharide helices solved prior to 1979 have appeared in the volumes published between 1967 and 1982.2-6 The first was a review on X-ray fiber diffraction and its application to cellulose, chitin, amylose, and related structures, and the rest were bibliographic accounts. Since then, X-ray structures of several new polysaccharides composed of simple to complex repeating units have been successfully determined, thanks to technological advances in fiber-diffraction techniques, the availability of fast and powerful computers, and the development of sophisticated software. Also, some old models have been either re-... 

Figure 4 is a set of contour plots of data derived from three Standard Pole Figure scans on a highly oriented specimen of linear polyethylene. The contour plotting software establishes a set of intensity levels that span the data in the diffraction data file. 

Computer software packages assist in matching the unknown diffraction patterns with a stored database. Problems arise if the sample contains more than one mineral species, since the pattern for each species gives rise to a complex overlapping pattern that cannot be easily interpreted. If one species can be easily identihed and its reflections subtracted from the pattern, it may then be possible to identify a second species. Three species becomes even more complicated. In such circumstances it is advisable if possible to physically sort ( pick ) the sample into different minerals under the microscope before... 

XRD Characterization The powder x-ray diffraction of the mechano-chemically milled complex borohydride has been carried out by the Philips X pert diffractometer with Cu-Koi radiation of X= 5.4060 A. The incident and diffraction slit width used for the measurements are 1° and 2° respectively. The sample holder was covered with Polyethylene tape (foil) with an O-ring seal in an N2 filled glove box in order to avoid or at least minimize the 02/moisture pickup during the XRD measurements. The diffraction from the tape was calibrated without the actual sample and found to be occurring at 29 angles of 22° and 24°, respectively. The XRD phase identification and particle size calculation has been carried out using PANalytical X pert Highscore software, version l.Of. 

Structure refinement based on dynamical scattering was developed by Zandbergen and Jansen (Zandbergen et al, 1997 Jansen et al, 1998), known as the MSLS software. Electron diffraction from crystal regions with relatively homogenous thicknesses was used. Both the crystal orientation, crystal thickness and the atomic coordinates could be refined simultaneously. 

The lack of software for the decomposition method in two dimensions in application to electron diffraction texture patterns was avoided by Zvyagin and Zhukhlistov by using one-dimensional methods of intensity extraction. Later the decomposition method for one-dimensional radial profiles (starting at the centre of the diffraction pattern and passing through... 

Every software package aimed at extracting the information from data obtained from any kind of diffraction experiment gives certain information as output, namely... 

J.P. Momiroli, Electron Diffraction, Dedicated Software to Interpret LACBEDPattems USTL, Lille, France (1994)... 

We have developed a software package MSLS [1], in which multi-slice calculation software is combined with least squares refinement software used in X-ray crystallography. With multi-slice calculations which are standardly used for image calculations of HREM images, dynamic diffraction is taken into account explicitly. 

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